Refrigeration apparatus, including a system for cooling parts thereof



Aug. 30, 1949. Q I c, MEYER 2,480,497

REFRIGERATIOIi APPARATUS INCLUDING A SYSTEM FOR COOLING PARTS THEREOF Filed July 28, 1945 2 Sheets-Sheet 1 INVENTOR {M4, W

MATTORNEY Aug. 30, 1949. F. c. MEYER 2,480,497

REFRIGERATION APPARATUS INCLUDING A SYSTEM FOR COOLING PARTS THEREOF Filed July 28, 1945- 2 Sheets$heet v2 I II M 07 IN VEN TOR.

Patented Aug. 30, 1949 v oFric REFRIGERATION APPARATUS, INCLUDING A SYSTEM FOR COOLING PARTS EOF Fred C. Meyer, Dayton, Ohio, assignor ta Serve],

Inc., New York, N. 'Y., a corporation at Delaware Application July as, 1945, Serial No. comic 18 Claims. (Cl. 62-5) The present invention relates to refrigeration and more particularly to a cooling water system" for supplying cooling medium to one or more elements of a refrigeration system as needed. The term cooling water system is used generically and is intended to include any cooling medium.

One of theobjectsof the present invention is to control the flow of cooling medium through an element of a refrigeration system in'accordance with the temperature of the medium leaving the element.

. Another object of the invention is to provide a cooling water system for causing the flow of cooling medium through a plurality of elements in succession and separately controlling the flow through each element.

Another object is tocirculate a limited amount of cooling medium through each. element so that each control is immediately responsive to temperature changes in the element.

Another object is to provide a cooling water system of the type indicated which is adapted to supply cooling medium to the second of a plurality of elements when the main path offlow through the first element is closed.

Still another object is-to provide a system of the type indicated-in which the flow of cooling medium is automatically stopped during an on cycle of the refrigeration apparatus and automatically started at the beginning of an on cycleof the refrigeration apparatus.

These and other objects will become more apparent from the following description and drawings in which like characters denote like parts throughout the several views. 'It is to be expressly understood, however, that the drawings are for the purpose of illustration only and not a definition of the limits of the invention, reference being had for this purpose to the appended claims. In the drawings:

Fig. 1 is a diagrammatic view of an absorption refrigeration system showing the cooling water system of the present invention applied to use with city water;

Fig. 2 is a sectional viewof the valve for controlling the flow of cooling medium through the absorber;

Fig. 3 is a sectional view of the valve for controlling the fiow of cooling medium throughlthe condenser; and Y Fig. 4 is a diagrammatic view of a modified cooling tower.

While the present invention may beapplied to use with any refrigeration system having an system to adapt it for use with a cooling l2 and flash chamber IS. The liquid refrigerant evaporates at a low pressure and temperature in the evaporator ill with consequent absorption'of heat from the ambient, such as a stream of air flowing over the exterior surface of the tubes M and finsit of the evaporator. The refrigerant vapor formed "in the evaporator l0 flows to an absorber Iii-in which the vapor is absorbed into a liquid absorbent such as, for example, a water solution of lithium chloride, lithium bromide, or the like. I l

The absorption liquid enriched with refrigerant is conductedfrom the absorber it to a generator ill in a path of flow including a conduit I8, liquid heat exchanger i9, conduit 26, vessel 2| and conduit 22. Within the generator H, a plurality of riser tubes 23 are enclosed within a shell 26 forming a chamber to which steam is supplied through a conduit 25 from a boiler 25. The heating of the riser tubes 23 by the steam causes refrigerant vapor to be expelled from the absorption solution and the expelled vapor is effective to raise the absorption liquid by gas or vaporlift action.

The expelled vapor passes from the upper ends of the riser tubes 23 into a vapor separatnig chamber 21 having baflles 28 therein and thence flows through a conduit 29 to the condenser E l in which the vapor is liquefied. The liquid refrigerant formed in the condenser ll flows by gravity into the U-shaped tube [2 to the upper part of'the evaporator III as explained above to complete the refrigerating cycle. v

The raised absorption liquid from which refrigerant vapor has :been expelled is conducted three separate chambers 49, 50 and 5|.

- ential between the high and .low pressure sides 01 thesystem is maintaned by liquid columns in the up-leg or the U-shaped tube l2 between the condenser H and evaporator l and in the conduits I6 and 3| connecting the absorber I5 and heat exchanger IS. The liquid level in the U-shaped tube I2 is indicated by the reference character X; the liquid levels in the conduit l8 and vessel 2| connected thereto through the heat exchanger I9 are indicated by the reference characters W and Y: and the liquid level in the conduit 39 connectedto the conduit 3| through the heat exchanger I9 is indicated by the reference character Z.

In an absorption refrigeration system as described above, the heat of condensation must be removed from the condenser II and the heat of absorption of refrigerant vapor in the absorbent must be removed from the absorber l5. As illustrated in Fig. 1, a surface type condenser is provided having inlet and outlet headers 33 and 34 connected by tubes for circulating a cooling medium therethrough. In the absorber H; a bank of pipes or coils 35 are provided for circulating a cooling medium and the bank of coils are connected by an inlet header 36 and an outlet header 31. The bank of coils 35 are positioned directly below the liquid distributor 32 in the absorber l5 so that absorption solution trickles over the exterior or the cooling coils to facilitate the transfor of heat.

In accordance with the present invention, a'

novel cooling water system and control is provided for supplying a cooling medium such as water to the bank of coils 35 in the absorber l5 and to the condenser II as needed. The cooling medium may be supplied from a city main as illustrated in the embodiment of the invention.

path of flow including the conduit 38, valve 39 and conduit 40. The cooling medium flows from the outlet header 31 of the bank of coils 35 in the absorber Hi to the inlet header 33 of the condenser H in a path or flow including the conduit 4|,

valve 42 and conduit 43. Cooling medium flows from the outlet header 34 of the condenser through a conduit 44 which may be connected to a waste pipe or the like. The flow of cooling medium through the coils 35 in the absorber I6 is controlled by the valve 39 and the flow of cooling medium through the condenser H is controlled by the valve 42.

The control valve 39, illustrated in detail in Fig. 2, comprises a valve body 45 having an inlet port 45 and an outlet port 41 for connection with the conduits 38 and 48, respectively. A septum 49 in the valve body 45 divides the interior into The septum has ports 52 and 53 connecting the chamber 49 with the chambers 55 and 5| and is provided with valve seats 54 and 55 surrounding the ports. A valve stem 55 slides in guideways 51 and 58 at the top and bottom or the valve body 45 and mounts valve plates 59 and 50. The valve stem 56 is moved to the position illustrated in Fig. 2 by asprlng 6| in the guideway 58 to close the port 52 and is operated in the opposite direction by a thermostat to open the port.

nected to the bellows by a capillary tube 54, see

Fig. 1. The bellows 52, bulb 63 and capillary tube 54 contain an expansible fluid which when heated expands the bellows to depress the valve stem 55. The bulb 53 of the thermostat is arranged in heat conducting relationship with the conduit 4| so that operation of the thermostat is responsive to the temperature of the cooling medium leaving and into the chamber 5|.

the absorber l6. When the temperature of the cooling medium leaving the absorber I5 is sufficiently low, the. valve plate 59 engages the valve seat 54 to close the port 52, see Fig. 2, but when the temperature of the cooling medium leaving the absorber increases to a predetermined value the thermostat operates the valve stem 56 to open the port 52.

Cooling medium also is supplied to the condenser through a branch conduit 55 connecte'dbetween an outlet port 55 in the valve body and the conduit 4|. When the valve stem 55 is in the position illustrated in Fig. 2, cooling medium entering the chamber 49 of the valve 39 from the inlet conduit 38 will flow through the port 53 The cooling medium then will flow from the chamber 5| through the outlet port 66 and conduit 55 to the conduit 4|. Thus, the cooling water system of the present invention includes a branch for delivering cooling medium through the absorber l5 and a branch for delivering cooling medium around the absorber for supplying it to the condenser II without first passing through the absorber. When the stem 55 of the valve 39 is first operated by the bellows 52, cooling medium may flow from the chamber 49 through both of the ports 52 and 53 to the chambers and 5| and from the chambers through both branches. When the valve stem is operated by the bellows 52 to engage the valve plate with the valve seat 55 all of the cooling medium flows through the port 52 and conduit 49 to the banks of coils 35 in the absorber I5 and thence flows through the conduit 4| to the condenser The valve 42 for controlling the flow of cooling medium through the condenser II is shown in detail in Fig. 3. The valve 42 comprises a housin 68 having an inlet port 69, outlet port In and a septum II for dividing the interior of the housing into chambers 12 and I3. The septum II' has a port I4 with a valve seat I5 surrounding the port. A valve stem I5 is slidably mounted in guides 11 and I9 in the valve housing 58 and mounts a valve plate I9 for engagement with the valve seats I5. The valve stem I6 is operated to the closed position illustrated in Fig. 3 by aspring 80 and is operated to open the valve by the bellows 8| of a thermostat. The thermostat comprises the bellows 8| connected to operate the valve stem I5 and a bulb 82 connectedto the bellows through the capillary tube 83, see Fig. 1. The bellows 8|, bulb 82 and capillary tube 83 contain an expansible fluid and the bulb is arranged in heat con- The thermostat comprises a bellows 62 conducting: relation to the conduit 44 so that the valve plate 19 is opened in response to a predetermined temperature of the cooling medium leaving the condenser -As the movement of the valve plate I9 is directly proportional to the temperature of the cooling medium leaving the condenser I, it will supply cooling medium to the condenser in direct proportion to the need. It will be observedth'at in accordance with the cooling system as thus far described, the flow of cooling medium through the coils 35 in the absorber I5 and through the condenser II is controlled individually by the valves 39 and 42 in accordance with the need. as determined bythe temperature of the cooling medium leaving the 1 elements.

The cooling water system of the present invention also provides for bypassing a small. amount of cooling medium around the valves 39 and 42 to cause circulation in the absorber coils 35 and condenser I I. The purpose of such circulation is to render thethermostat' bulbs 63 and 82 immediately responsive to temperature changes in the absorber I6 and condenser II. The bypass around the valve 38 comprises a conduit 85 having its opposite ends connected to the conduits 38 and 48, see Fig. 1. A manually adjustable valve 86 is provided in the bypass conduit 85 for permittingthe flow of a predetermined small amount of cooling medium through the coils 35 in the absorber I6. The bypass valve 86 has a passageway 81 therein with a conical valve seat 88 and a screw-threaded valve stem 89 provided with a tapered end 98 for cooperation with the valve seat 88. By turning the valve stem 89, the amount of cooling medium flowing through the bypass conduit 85 may be adjusted.

A similar bypass is provided around the valve 42 and comprises a. conduit 82; a valve-93 and a conduit 84. One end of the conduit 92 is connected to the conduit 4I adjacent the valve 42 and its opposite end is connected to the inlet port of the valve 93. The conduit 94 is connected between the outlet port of the valve 83 and the conduit 43 adjacent the valve 42. Valve 83 is provided with a conical valve seat 85 and a valve stem 96 having a conical end for cooperation with the valve seat. A spring 91 operates the valve stem 96 to close the valve and a solenoid winding 98 surrounds the valve stem and is operative when energized to actuate the valve stem against the action of the spring 81 to open the valve.

The valve 93 is closed by the spring 91 to prevent the circulation of any cooling medium during an off cycle of the refrigeration system and is-opened by the solenoid winding 98 to open the bypass during an on cycle of the refrigeration system. The solenoid winding 88 is connected in the electrical control circuit for the refrigeration apparatus including the electromagnetically operated fuel valves I88 and IN. The fuel valves I88 and IN are similar to the valve 93 and include solenoid windings I82 and I83 for opening the valves and springs I84 for closing the valves. The energization of the solenoids 98, I82 and I83 of the valves 93, I88 and IN is controlled by toggle switches I85, I88 and I81 arranged in parallel branch circuits connected to the line I81a. The switches I85, I86 and I81 are operated .by a slidable bar I88 and the arrangement of the switches is such that the switches I85 and I86 will be closed simultaneously while the closing of the switch I81 requires additional movement of the bar. The bar I 88:: is actuated to open or close the switches I85, I88 and I81 by a thermostat including a bulb I89, a bellows H8 and a capillary tube III connecting the bulb andbellows. One end of the bellows II8 abuts the end of a casing H2 and its opposite end is connected by a rod I I3 to one end of a lever II4 pivotally connected to the casing II2 intermediate its ends.

The bulb I89 of the thermostat is responsive to the temperature of the air flowing through the evaporator tubes I5 and upon an increase in the temperature the thermostat bellows II8 will operate through the rod I I3, lever I I4 and bar I88 to close the switches I85 and I88. Upon a further increase in temperature. the thermostat is operative through the rod II3, lever H4 and bar I88 to close the switch I81. One embodiment of the invention now having been described in detail the mode of operation of the cooling water system is explained as follows.

'For purposes of description, let it be assumed that the refrigeration apparatus is on an off-cycle at which time the temperature of the air to be conditioned is at the desired low temperature, the switches I85, I86 and I81 are open and the bypass valve 93 is closed so that no cooling medium is circulating in the cooling water system. As no heat is being transferred in the absorber I6 and condenser II the temperature of the cooling medium in the conduits 4| and 44 is sufllciently low so as to maintain the valves 38 and 42 in the closed positions illustrated inFigs. 2 and 3.

Upon a predetermined increase in the temperature of the air to be conditioned the fluid in the thermostat bulb I89 will expand the bellows II8 which operatingthrough the rod II3, lever H4 and bar I88 will actuate the switches I85 and I86 to closed position. Closing of the switch I85 will energize the solenoid winding 98 to open the bypass valve '93 against the action of the spring 91. When the bypass valve 93 is opened, a limited amount of the cooling medium will'flow through the valve 86 in the bypass conduit 85 to cause a circulation of the cooling medium through the cooling coils 35 in the absorber I6. The cooling inedium leaving the coils 35 in the absorber I8 will flow through the conduit 4 I, conduit 92, valve 93 and conduit 94 of the bypass around the valve 42 and then through the conduit 43 to the condenser II. Flow of a limited amount of the cooling medium through the by-pass around the valve 42 will cause a circulation of cooling medium in the condenser II. The coolingmedium is circulated in the absorber I6 and condenser II so that the bulbs thermostats will respond quickly to any temperature change in the absorber and condenser.

Simultaneously with the opening of the bypass valve 93 the solenoid winding I82 is energized by 45 the closing of the switch I86 to open the fuel valve I 88. When the fuel valve I88 has been opened, heat will be supplied to the boiler 26 'to generate steam which will flow through the conduit 25 to the generator I1. Steam in the gen- 50 erator I1 expeis refrigerant vapor from the absorption liquid in the tubes 23 which rises through the tubes to the separating chamber 21. The refrigerant vapor rising in the tubes 23 also acts to lift the absorption solution by a vapor lift 55 action into the separating chamber 21. The refri'gerant vapor then flows through the conduit 29 to the condenser I I where it is condensed to a liquid by the transfer of heat to the cooling medium flowing 'therethrough. Liquid refrigerant in the condenser I I then flows through the U- shaped tube I2 to the evaporator I8 where it evaporates at low pressure and temperature to produce the refrigerating effect. The refrigerant vapor in the evaporator I8 flows to the absorber Iii/where it is absorbed in the weak absorption solution flowing thereto from the separating chamber 21 of the generator through a path of flow including the conduit 38, liquid-heat exchanger I9, conduit 3I and liquid distributor 32. 7 The heat caused by the absorption of refrigerant vapor in the weak absorption solution is transferred to the cooling'medium in the coils 35 in the absorber.

The transfer of heat from the refrigerant vapor in the condenser II increases the temperature of 63 and 82 of the valve operating.

he coolin medium flowing therethrough and exhausting tirrough the conduit 44. When the temperature of the cooling medium leaving the condenser II rises to a predeterimned value, the fluid in the thermostat bulb 82 in contact with the conduit 44 will expand the bellows BI of the thermostat, see Fig. 3, to 'depress the valve stem 16 against the action of the spr1ng 8ll to open the port I4. Cooling medium then will flow from the conduit 4I into the chamber I2 of the valve 42 and through the port I4 to chamber I3 and thence through the conduit 43 to the condenser II. Cooling medium is supplied to the conduit 4I either through the absorber I5 or through the branch conduit 65 connected to the port 66 of the valve 39. It will be apparent that even though the port 52 of the valve 39 is closed an m le su ly of cooling medium will be supplied Elie co n zluit 4I through the conduit 65. Referring to Fig. 2 of the drawings, cooling medium from the supply main enters the chamber 49 of the valve 39 through the conduit 38 and thence flows through the port 53 to the chamber I and from the chamber 5I through the conduit 65 to the conduit 4|. As the temperature of the cooling water leaving the condenser II continues to increase the valve 19 will continue to open the port I4 until the temperature of the medium leaving the condenser is reduced to a predetermined value. It will be apparent, therefore, that the valve 42 is modulated in response to the temperature of the cooling medium leaving the condenser 'I I to supply the cooling medium to the condenser as needed.

When the temperature of the cooling medium leaving the coils 35 in the absorber I6 rises to a predetermined value the thermostat bulb 63 in contact with the conduit 4| adjacent the absorber will expand the bellows 62 to depress the valve stem 55 against the action of the spring 6| to open the port 52, see Fig. 2. Cooling medium then flows through the conduit 38 into the chamber 49 and through the port 52 to the chamber 50 and thence flows through the conduit 40 to the header 33 connecting the banks of coils 35. Simultaneously with the opening of the port 52 by the movement of the valve plate 59, the valve plate 69 on the valve stem 55 moves to close the port 53. As the temperature of the cooling medium leaving the coils 35 of the absorber I6 continues to increase the valve stem 56 of the valve 39 will be depressed until the port 52 is fully open and the port 53 is completely closed. As the thermostat bulb 63 is responsive to the temperature of the cooling medium leaving the absorber I6, the valve 39 will be modulated to supply cooling medium to the absorber as needed.

If the temperature of air to be conditioned continues to rise the thermostat bellows III) will operate the bar I98 to close the switch I07 to energize the solenoid winding I 93 and open the fuel valve IIlI. Upon an increase in the heat supplied to the boiler 26 more steam will be supplied to the generator II, more refrigerant vapor will be expelled in the generator and more heat will be transferred in the condenser II and absorber I6. Such increase in the heat transfer in the condenser II and absorber I6 will increase the temperature of the cooling medium flowing from the absorber and condenser, respectively, and the thermostat bulbs 63 and 82 being responsive to the temperature of the cooling medium in the conduits M and 44 will operate the valves 39 and 42 to supply cooling medium to the elements as needed.

In Fig. 4, a cooling water system of modified arrangement is illustrated to adapt the present invention for use with a cooling tower. The modified arrangement in Fig. 4 is applied to the refrigeration system of Fig. 1, but in the illustrated embodiment only the absorber I6 and condenser I I are shown. In this modification, however, the conduit 38 is connected to the outlet of a pump I20 for receiving liquid from a cooling tower I2I and the conduit 44 from the outlet of the condenser II is connected to return the cooling medium to the cooling tower. The conduit 36 is connected to the absorber through the valve 39 and bypass in a manner identical with that illustrated and described in the embodiment of the invention illustrated in Fig. 1. The valve 39 is controlled by the same thermostat including the bulb 63 in heat conducting relationship with the conduit 41 and the bellows 62. The port 66 of the valve 39 is connected to the conduit 4| by the same branch conduit 65. In place of the valve 42, however, a valve I22 and bypass I23 identical with the valve 39 and bypass 85 are provided between the conduit II and conduit 44. A branch conduit I25 connects the outlet port I26 of the valve I22 with the conduit 44.

In the modified arrangement illustrated in Fig. 4, the cooling tower I 2|, conduits 38 and 44 together with the paths of flow through the absorber I6 and condenser II provide a closed circuit for the recirculation of the cooling medium. Cooling medium is supplied to the absorber through the bypass 85 and valve 39 in the manner as explained with respect to the embodiment of the invention illustrated in Fig. 1. Cooling medium is supplied to the condenser II through one or the other of the branch conduits M and .65 and thence through the bypass I23 and valve I22. If both of the valves 39 and I22 are closed a limited amount of cooling medium will merely circulate through the absorber I6 and condenser II. The major portion of the cooling medium will continuously circulate through the conduit 38, conduit 65, conduit 4|, conduit I25, conduit 44 and cooling tower I2I. This continuous circulation of the cooling medium through the cooling tower I2I will reduce its temperature. As the transfer ofheat in either the condenser II or absorber I6 increases, the valves I22 or 39 will progressively open to supply cooling medium to the particular element as needed. Simultaneously with the increase in flow of cooling medium through the valves 39 and I22 the flow through the branch conduits. 65 and I25 will decrease. This operation will continue until all of the flow is through the absorber I 6 and condenser II at which time no flow will occur in the branch conduits 65 and I25.

It will now be observed from the foregoing description that the present invention provides for stopping the how of any cooling medium through the cooling water system during an off-cycle and for permitting the circulation of a limited amount of cooling medium through the elements during an on-cycle. It will further be observed that the present invention provides for individually controlling the amount of cooling medium flowing through each of a plurality of elements in response to the temperature of the cooling medium leaving the particular element. It will still further be observed that the present invention provides for supplying an adequate amount of cooling medium to each of the elements regardless of the rate of flow through another element.

While several embodiments of the invention are 9 herein illustrated and described it will be understood that further modifications may be in the construction and arrangement of the parts without departing from the spirit or scope of the invention. For example, the construction and arrangement illustrated in Fig. 4 may be further modified to adapt several refrigeration units to be supplied with cooling medium from a single cooling tower. In the claims the term "through when used to define the fiow of cooling medium with respect to an element such as the absorber or condenser is-to be construed to mean in heat exchange relation with the element, whether internally or externally applied; and the term around when used to define the fiow of medium with respect to such element is to be construed to mean by-passing or out of heat exchange relation with the element. Therefore without limitation in these respects, the invention is defined by the following claims.

What is claimed is:

1. In absorption refrigerating apparatus, a generator, a condenser, an evaporator, an absorber, conduits interconnecting the elements to provide circuits for the circulation of refrigerant and absorbent, a cooling system for fiowing a cooling medium through the absorber and condenser successively, valves in the cooling system for controlling the flow of the cooling medium through the absorber and condenser, and a separate thermostat for operating each valve and so arranged as to be responsive to the temperature of the cooling medium flowing from the absorber and condenser respectively.

2. In absorption refrigerating apparatus comprising a generator, a condenser, an evaporator, an absorber, conduits interconnecting the elements to provide circuits for the circulation of refrigerant and absorbent, a cooling system for flowing a cooling medium through the absorber and condenser successively, valves in the cooling system for controlling the flow of cooling medium through the absorber and condenser respectively, a bypass around each valve to permit a limited flow of the cooling medium through the absorber and condenser, and thermostats. so arranged as to be responsive to the temperature of the cooling medium flowing from the absorber and condenser and connected to operate the respective valves.

3. In absorption refrigerating apparatus comprising a plurality of elements interconnected to provide circuits for the circulation of refrigerant and absorbent, a cooling system for flowing a cooling medium through a plurality of the elements successively, said cooling system having a branch for delivering cooling medium through the first element and a branch for delivering cooling medium around the first element, a valve for simultaneously opening one branch and closing the other branch of the cooling system, and a thermostat so arranged as to be responsive to the temperature of the cooling medium leaving the first element for operating the valve.

4. In an absorption refrigerating apparatus comprising a generator, a condenser, an evaporator, an absorber, conduits interconnecting the elements to provide circuits for the circulation of refrigerant and absorbent, a cooling system for flowing a cooling medium through the absorber and condenser successively, said cooling system having a branch for delivering a cooling medium through the absorber and a branch for delivering cooling medium around the absorber,

a valve for simultaneously opening one branch I so arranged as to be responsive to the temperature of the cooling medium leaving the absorber for operating the valve.

*5. In an absorption refrigerating apparatus comprising a plurality of elements interconnected to provide circuits for the circulation of refrigerant and absorbent, a cooling system for flowing a cooling medium through. a plurality of the elements successively, said cooling system having a branch for delivering cooling medium through the first element and a branch for delivering cooling medium around the first element, a first valve for simultaneously opening one branch and closing the other branch, a second valve for controlling the flow of cooling medium through the last element in the cooling system, and thermostats so arranged as to be responsive to the temperature of the cooling medium flowing from the first and last elements for operating the first and second valves respectively.

6. In an absorption refrigerating apparatus comprising a generator, a condenser, an evaporator, an absorber, conduits interconnecting the elements to provide circuits for the circulation of refrigerant and absorbent, a cooling system for flowing a cooling medium through the absorber and condenser successively, said cooling system having a branch for delivering a cooling medium through the absorber and a branch for delivering cooling medium around the absorber, a valve for simultaneously opening one branch and closing the other branch, said valve controlling the flow of cooling medium through the absorber, a second valve in the cooling system circuit for controlling the fiow of cooling medium through the ments successively, said cooling system having abranch for delivering cooling medium through the first element and a branch for delivering cooling medium around the first element, a first valve "for simultaneously opening one branch and.

closing the other branch, a second valve for controlling the fiow of cooling medium through the last element in the cooling system, thermostats so arranged as to be responsive to the temperature of the cooling mediumficwing from the first and last elements for operating the first and second valves respectively, a bypass around the second valve for permitting the flow of a limited amount of cooling medium through the-last element, and means for closing the bypass.

8. In an absorption refrigerating apparatus comprising a plurality of elements interconnected to provide circuits for the circulation of refrigerant and absorbent, an electric circuit for controlling the. operation of the refrigeration system, a cooling system for flowing a cooling medium through a plurality of elements successively, said cooling system having a branch for delivering cooling medium'through the first element and a branch for delivering cooling medium around the first element, a first valve for simultaneously opening one 'branch and closing the other branch, a second valve for controlling the flow of cooling medium through the last element, thermostats so arranged as to be responsive to the temperature of the cooling medium flowing from the first and last elements for operating the first and second valves respectively, a bypass around the second valve for permittingthe flow of a limited amount of cooling medium through the last element, and an electromagnetically op erated valve in the bypass and responsive to the energi'zation and deenergization of the control circuit for controlling the flow of cooling medium through the bypass.

9. In an absorption refrigerating apparatus comprising a plurality of elements interconnected to provide circuits for the circulation of refrigerant and absorbent, an electric circuit for controlling the operation of the refrigeration system, a cooling system for flowing a cooling medium through a plurality of elements successively, said cooling system having a branch for delivering cooling medium through the first element and a branch for delivering cooling medium around the first element, a first valve for simultaneously opening one branch and closing the other branch, a second valve for controlling the flow of cooling medium through the last element, thermostats so arranged as to be responsive to the temperature of the cooling medium flowing from the first and last elements for operating the first and second valves respectively, a bypass around the second valve for permitting the flow of a limited amount of cooling medium through the last element, a valve in the bypass, an electromagnet in the electric control circuit for operating the valve to open the bypass when the control circuit is energized, and a spring for operating the valve to close the bypass when the electric control circuit is deenergized.

10. In an absorption refrigerating apparatus comprising a generator, a condenser, an evaporator, an absorber, conduits interconnecting the elements to provide circuits for the circulation of refrigerant and absorbent, a cooling system for flowing a cooling medium through the absorber and condenser successively, said cooling system having a branch for. delivering a cooling medium through the absorber and a branch for delivering cooling medium around the absorber, a valve for simultaneously opening one branch and closing the other branch, said valve controlling the flow of cooling medium through the absorber, a second valve in the cooling system for controlling the flow of cooling medium through the condenser, separate thermostats so arranged as to be responsive to the temperature of the cooling medium leaving the absorber and condenser for operating the first and second valves respectively, a bypass around the first valve, a manually adjustable valve for permitting the flow of a limited amount of cooling medium through the absorber, a bypass around the second valve permitting the flow of a limited amount of cooling medium through the condenser, a valve in the last named bypass, an electromagnet for operating the valve to open the bypass, and a spring for operating the valve to close the bypass.

11. In refrigerating apparatus comprising a plurality of elements interconnected for the circulation of a refrigerant, a cooling tower, a cooling system including the cooling tower for circulating a. cooling medium, said cooling system having a branch including at least one of the elements of the refrigerating apparatus for circulating the cooling medium therethrough and a branch for circulating the cooling medium around the element, a valve for simultaneously opening one of the branches and closing the other branch, and a thermostat so arranged as to be responsive to the temperature of the cooling medium leaving the element for the operating valve.

12. In absorption refrigerating apparatus comprising a plurality of. elements interconnected for the circulation of refrigerant and absorbent, a cooling tower, a cooling system including the cooling tower for circulating the cooling medium through aplurality of the elements, said cooling system having a branch for circulating cooling medium through one of the elements and a branch for circulating cooling medium around the element, a first valve for simultaneously opening one of the branches and closing the other branch, a thermostat responsive to the temperature of the cooling medium leaving the first element for operating the valve, a second valve for controlling the flow of cooling medium through the last element, and a thermostat so arranged as to be responsive to the temperature of the cooling medium leaving the last element for operating the second valve.

13. In absorption refrigerating apparatus comprising a generator, a condenser, an evaporator, an absorber, conduits interconnecting the elements to provide circuits for the circulation of refrigerant and absorbent, a cooling tower, a cooling system including the cooling tower, ab-

sorber and condenser for circulating a cooling medium therethrough, said cooling system having branches through the absorber and condenser and branches around the absorber and condenser, valves in the circuit for controlling the flow through the absorber and condenser, and thermostats so arranged as to be responsive to the temperature of the cooling medium leaving the absorber and condenser for operating the respective valves.

14. In absorption refrigerating apparatus comprising a generator, a condenser, an evaporator, an absorber, conduits interconnecting the elements to provide circuits for the circulation of refrigerant and absorbent, a cooling tower, a

" cooling system including the cooling tower, ab-

sorber and condenser for continuously circulating a cooling medium, said cooling system having one set of parallel branches with one branch of said set located in the absorber and the other branch of said set by-passing the absorber and another set of parallel branches with one branch located in the condenser and the other branch by-passing the condenser, valves for controlling the flow of cooling medium through each set of the parallel branches of the circuit, each valve simultaneously opening one branch and closing the other branch, and thermostats so arranged as to be responsive to the temperature of the cooling medium leaving the absorber and condenser for operating the respective valves.

15. In refrigerating apparatus comprising a plurality of elements interconnected for the circulation of a refrigerant, a'cooling system including a cooling tower and a plurality of elements of the refrigerating apparatus, said cooling system having a plurality of pairs of parallel branches connected in series, one of the branches of each pair being adapted to circulate cooling medium through one of the elements of the apparatus to be cooled and the other branch being adapted to circulate cooling medium around the element, a modulating valve for each pair of parallel branches for simultaneously opening one branch and closing the other branch, and a thermostat for each valve so arranged as to be Macao:

responsive to the temperature of the cooling medium flowing from the element to be cooled, each thermostat being connected to operate its respective valve.

16. In refrigerating apparatus comprising a plurality of elements interconnected for the circulation of a refrigerant, a cooling system including a cooling tower and a plurality of elements of the refrigerating apparatus, said cooling system having a plurality of pairs of parallel branches connected in series, one of the branches of each pair being adapted to circulate cooling medium through one of the elements of the apparatus to be cooled and the other branch being adapted to circulate cooling medium around the element, a modulating valve for each pair of parallel branches for simultaneously opening one branch and closing the other branch, a thermostat for each valve so arranged as to be responsive to th temperature of the cooling medium flowing from the element to be cooled, each thermostat being connected to operate its respective valve, and a by-pass around each valve for circulating a limited amount of the cooling medium through the elements to be cooled so that the thermostats will respond to an increase in the temperature in the elements.

17. In refrigerating apparatus having a plurality of elements interconnected to provide a circuit for refrigerant, a cooling system in addition to the refrigerant circuit and having a branch for delivering cooling medium through one of the elements of the refrigerant circuit and a branch for delivering cooling medium around the element, a. valve for opening the branch for deliv ering cooling medium around the element, and a thermostat so arranged as to be responsive to the temperature of the cooling medium leaving the element and connected to operate-the valve.

18. In refrigerating apparatus having a plurality of elements interconnected to provide a circuit for refrigerant, a cooling system in addi- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,133,962 Shoemaker Oct. 25, 1938 2,282,503 Thomas et al. May 12, 1942 2,356,638 Williams Aug. 22, 1944 2,365,797 Bichowsky Dec. 26, 1944 2,378,177 Bichowslw June 12, 1945 

